| A | B |
|---|
| atom | smallest piece of an element that has all the properties of that element |
| atomic structure | the number and arrangement of protons, neutrons and electrons in an atom |
| chemical change | the change of a substance into a new substance that has different properties |
| chemical equation | model of chemical changes that illustrates how elements become rearranged in a chemical reaction |
| chemical formula | shorthand way to represent a compound (consists of chemical symbols and subscripts) |
| chemical reaction | change in which one or more substances are converted into different substances |
| chemical symbol | shorthand way to write the name of an element |
| compound | matter formed when two or more elements join chemically in exact ratios to form new materials that have different properties |
| density | amount of mass a substance has for a given volume |
| element | matter made of only one kind of atom |
| mass | the amount of matter in an object |
| matter | anything that takes up space and has mass |
| electron | negatively charged particle that moves around the nucleus of an atom |
| model | structure or diagram that represents an object or event |
| molecule | combination of two or more atoms (like or unlike) |
| neutron | neutral particle found in the nucleus of an atom |
| nucleus | atom's dense center where most of mass of an atom is is found |
| Periodic Table | organizes the elements according to atomic number |
| atomic number | number of protons an atom has; each element has a unique one of these |
| physical change | when the size, shape, state or phase of matter changes |
| proton | positively charged particle found in the nucleus of an atom |
| subscript | number of atoms for a particular element represented by a small number to the right of an element's symbol |
| volume | the amount of space matter takes up |
| weight | measure of the pull of gravity on an object |
| coefficient | number placed in front of a chemical reactant or product that helps balance an equation |
| reactants | materials that are started with in a chemical reaction |
| products | materials that are made in a chemical reaction |
| mixture | composed of materials that are physically combined (in any amounts); properties of the combined materials do not change |
| molecule | smallest part of a compound |
| elements found in Earth's crust | oxygen, silicon, aluminum, potassium, calcium, sodium, magnesium, |
| elements found in Earth's atmosphere | oxygen, nitrogen |
| elements found in Earth's oceans | chlorine, sodium, oxygen, hydrogen |
| elements found in living things | nitrogen, carbon, hydrogen, oxygen |
| nucleus | contains protons and neutrons |
| electron cloud model | current model of an atom where a "cloud" represents an area where electrons are expected to be found |
| Bohr model | model of an atom that shows electrons in energy levels |
| solution | special type of mixture in which one substance dissolves in (is spread evenly throughout) another substance |
